1. Technical Field
This disclosure relates generally to piezoelectric microelectromechanical system (MEMS) sensors, and, more particularly in some embodiments, a high performance piezoelectric MEMS hydrophone for underwater acoustic signal detection.
2. Description of the Related Art
Hydrophones are devices typically used to detect underwater sounds. They are widely used, for example, in marine oil and gas detection systems, sonar systems, underwater communication systems and diving equipment, etc. For example, in marine seismic exploration, hydrocarbon bearing formations may be located by generating acoustic source signals in a body of water, and then detecting acoustic signals that result, at least in part, from the acoustic source signals interacting with ground formations under the body of water. Many hydrophones include piezoelectric materials that, when deformed by the acoustic pressure of a sound wave, generate electricity. Electrodes may be used to detect generated electricity—the greater the acoustic pressure applied, the greater the induced charge. In many instances, good low-frequency performance is desired from hydrophones (ranging from several Hz to several kHz) because of large transmission loss and the short transmission distance of high-frequency signals in the water. In addition, large dynamic range, low acoustic impedance, and good linearity are also desirable design criteria for a hydrophone.